Abstract: The goal of this project is to test how to deliver intracortical microstimulation (ICMS) effectively to convey feedback or instructional information for potential use in neural prostheses. Significant research has focused on developing brain machine interfaces (BMIs) as a rehabilitative means for restoring function to individuals with a neurological disorder or injury. One aspect that has been missing in these BMI results is the incorporation of sensory feedback. Proprioceptive feedback proves to be an important component of natural hand and arm movements. Without subconscious proprioceptive feedback informing the brain about position and movements, motor control relies entirely on visual feedback to ensure tasks are executed correctly. For neuroprosthetic devices, feedback delivered to the nervous system eventually will be needed to improve performance and reduce reliance on visual feedback for manipulating the device. This afferent feedback will provide a means of ?closing the loop? to allow the user to make adjustments and provide a sense of embodiment. The present project will utilize a BMI environment in which an avatar hand is controlled voluntarily using neural signals. ICMS will be delivered to convey either feedback information about the movements and positioning of the avatar hand or instructive information about the target configuration for the hand. The choice of where to provide ICMS is based on existing views of how neural information flows during hand movements. To deliver sensory feedback about the movements of the avatar hand, ICMS will be delivered in the primary somatosensory cortex (S1), which has direct projections to the primary motor cortex (M1) and where we know ICMS can be perceived. To deliver instructional information about the target hand configuration, ICMS will be delivered in the ventral premotor cortex (PMv), which also has direct projections to M1 and receives visual information about target objects. In addition, the studies proposed here will test the general hypothesis that ICMS delivered in a specific context produces plastic changes in cortico-cortical connectivity.